Firearms that are discharged from the shoulder have generally been divided into two separate groups; rifles and shotguns. Rifles may be characterized as those firearms that are discharged from the shoulder and fire a single projectile a considerable distance at a specific target point and are aligned with said target point by means of accurate sights. Shotguns may be characterized as those firearms that are discharged from the shoulder and fire multiple projectiles a moderate distance at a specific target location and are aligned with said target location by means of pointing aids called ball or bead sights.
The advent of the rifled slug in the 1930's slightly blurred the distinction between rifles and shotguns. The rifled slug's relatively high mass and low muzzle velocity imparted to it the characteristics of relatively high shocking and knock down capabilities. At short ranges (less than 100 yards) these characteristics made the rifled slug an ideal load for the taking of deer in brushy and swampy areas.
It was almost universally believed at that time that the effective range of a rifled slug was about 50 yards. It has since been shown that much of the apparent ineffectiveness of the rifled slug at ranges beyond 50 yards was due in part to the marksman's inability to aim a shotgun accurately using only the ball or bead sight provided on most shotguns.
In the 1940's and 1950's many local governments became concerned about the use of high powered rifles in their areas. As a result of these concerns many governmental areas have been designated "shotgun only"areas for deer hunting. This compulsory use of the shotgun and slug for the taking of deer caused sportsmen and arms manufacturers to intensify their search for a means to provide a more rifle-like set of sights for use with a shotgun when the shotgun is employed in the shooting of rifled slugs. For reasons discussed in detail herein, a simple exchange back and forth between conventional shotgun sights and conventional rifle sights has not heretofore been shown to be practicable.